As a commercial helicopter pilot and instructor I'd like to share my thoughts on this tragic accident:

At Vauxhall Bridge (which is the vicinity of the Hyde Park Restricted area R157) the pilot is required to fly at a minimum of 1,400 feet unless he contacts the chief of police. In any case helicopters usually fly at the maximum permitted altitude of 1500 feet between Chelsea Bridge and Vauxhall Bridge and at 2000 feet to the East of Vauxhall bridge. The crane had a height of around 700 feet. One must ask why was the pilot at 700 feet, less than half the normal height?

Within the London Control Zone, Helicopters are flying on "Special Visual Flight Rules" and are required to have a visibility of 3km or more. What was the visibility at the time?

Was the pilot flying too fast for the meteorological conditions, considering he has to maintain 3km of ground is sight at all times? If the visibility deteriorated then why did he not slow down to or come to a hover or make a precautionary landing somewhere. Eg A park? My thoughts are this: Commercial helicopter pilots are under a lot of pressure to get somewhere. An Augusta 109 costs around £1500+/hr to operate. Every minute of flight time is another £25. The charter company would have almost certainly quoted the passenger a fixed cost for his journey. It is then up to the pilot to fly as quickly as possible from A to B to reduce costs for his company. This becomes a habit.

Why is air speed a factor? If the visibility is poor then slowing down to say 40kts gives you much more time to respond to obstacles that take you by surprise. Especially if you are flying extremely low. It's much easier to stop from 40 kts than it is from 80 kts. In fact it takes 4 times as long to slow down from 80 kts compared to 40kts, that's because kinetic energy is propositional to the square of the speed (KE=MV2). So if it takes 3 seconds to slow down from 40 kts to 0 kts then it would take 12 seconds to stop from 80kts.

Why was the pilot not in the middle of the Thames? Given that, not only is that a Helicopter Route, but if the visibility were very poor and the cloud low then following the Thames has these advantages:

- Very easy to navigate in poor visibility, just follow the river.
- The only obstacles would be the bridges themselves which only rise about 200, 300 feet above the water.

Why would a helicopter pilot fly very low over the banks of the river Thames taking himself into the vicinity of tall buildings?

I have two theories:

1. The pilot accidentally flew into cloud and was unable to see where he was going taking him off course. By the time he started to correct the action to get out of cloud is is too late and he hits the crane. But a pilot with 10,000 hrs of flight time would be very good a cloud avoidance, so this is confusing.

2. The pilot decoded the turn around and go back and in doing so this took him over the bank of the Thames. During a turn in forward flight height is more difficult to control and the pilot may have momentarily allowed the helicopter to rise 100 feet and risen into the cloud, gone back down a few seconds later and seen the crane at the last minute.

My conclusion is that the pilot being conscious of time and money was flying too fast for the conditions and accidentally flew into a cloud during a turn (to go back the way he came) which took him into the path of a crane and he was unable to slow down in time - again due to his high speed.

Let's not panic. Review and modify the rules if necessary, but a single event is not a trend no matter how impressive the TV pics are. Focus on where the real numbers are, like automobile fatalities and couch-potatoe life styles.

It makes a healthy sense that large cities in the developed world - like London and Paris - have adopted stringent restrictions on the traffic for helicopters within city limits which wisely is only allowed for emergency purposes. In Brazil there are no such restrictions and cities like S.Paulo - which have a chaotic and congested traffic system for a backlog of proper investment in mass transport - boasts its number of private helicopters in circulation as if it were a harbinger of the future. The fact that the whirlybirds can crash in densely crowded areas is just one side of the question. You also have to face their engine noise levels adding to an already highly stressing din of the plain traffic among other sources in large cities. Now they have started importing them to Belo Horizonte. It is crazy.